Fin and tube type heat exchanger



Dec. 14, 1965 c. s. slMPELAAR 3,223,153

FIN AND TUBE TYPE HEAT EXCHANGER Filed May 21. 1962 2 Sheets-Sheet 1Dec. 14, 1965 c. s. slMPELAAR FIN AND TUBE TYPE HEAT EXGHANGER 2Sheets-Sheet 2 Filed May 21, 1962 United States Patent O 3,223,153 FINAND TUBE TYPE HEAT EXCHANGER Clyde S. Simpelaar, Racine, Wis., assignerto Modine Manufacturing Company, a corporation of Wisconsin Filed May21, 1962, Ser. No. 196,114 Claims. (Cl. 165-152) This is acontinuation-in-part of application Serial No. 115,234, tiled June 6,1961, and now Patent No. 3,106,958.

This invention relates to a heat exchanger particularly of the iin andtube type wherein one fluid is confined within a conduit or tube whichhas attached thereto spaced tins for heat exchange with another fluidpassing around and between the tubes and fins.

In many types of heat exchangers it is customary to provide conduits andspecifically tubes for one fluid to flow therethrough and spaced ns incontact with these conduits between which another uid ows in order toprovide heat transfer between the two fluids. In my above copendingapplication it has been proposed to form these tins by bending acontinuous metal sheet which may be in strip form in a serpentine orsinuous arrangement with adjacent portions of the metal sheetconstituting the spaced ns and arranged against the outer surfaces ofthe fluid conduit in order to provide heat transfer therebetween andthus between the fluid within the conduit and the iluid pas-sing betweenthe tins.

One of the features of the present invention is to prov-ide a heatexchanger structure comprising a sinuous continuous metal sheet arrangedin adjacent pleats to form fins connected in series by side fold areasin which these fold areas have openings for permitting fluid flowthrough the openings to between the tins with the heat exchangerstructure also including means forming aligned iin openings forreceiving the fluid tubes.

Other features and advantages of the invention will be apparent from thefollowing description of certain embodiments thereof taken inconjunction with the accompanying drawings. Of the drawings:

FIGURE 1 is a fragmentary elevational view illustrating the general typeof heat exchanger with which the invention is concerned.

FIGURE 2 is a fragmentary elevational view of a metal sheet for formingone embodiment of the tins,

FIGURE 3 is Va sectional view through the embodiment of FIGURE 2 withspacer projections omitted for simplicity of illustration.

FIGURE 4 is a View similar to FIGURE 3 illustrating the folding of themetal sheet into adjacent pleats preparatory to forming the iinstructure with spacer projections omitted for simplicity ofillustration.

FIGURE 5 is a fragmentary sectional view through a completed heatexchanger utilizing the fin structure of this first embodiment.

FIGURE 6 is a side elevational view of the heat exchanger of FIGURE 5FIGURE 7 is a view similar to FIGURE 2 .showing a metal sheet used informing a second embodiment of the iin structure.

FIGURE 8 is a view similar to FIGURE 2 but showing a metal sheet used inproducing a third embodiment of the iin structure.

FIGURE 9 is a perspective view illustrating the fold form of theembodiment of FIGURE 8.

FIGURE 10 is a sectional View taken substantially along line lil-10 ofFIGURE 9. j

FIGURE 1-1 is a View similar to FIGURE 8 but illustrating a fourthembodiment of the invention.

FIGURE 12 is a view similar to FIGURE 9 but employing the fin structureof this fourth embodiment.

FIGURE 1 illustrates the type of heat exchanger uti- Patented Dec. 14,1965 liz-ing the present invention. Such a heat exchanger has many usessuch as for condensers for refrigeration systems. The heat exchangercomprises a plurality of fluid tubes 20 connected by closely spaced tins2'1. In the type of fn structure contemplated, these ns are made up ofadjacent pleats of a metal sheet or strip folded .to lie substantiallyparallel to each other so that the adjacent pleats constituting the finsare connected in series by side fold areas 22.

In 'the embodiment of FIGURES 2-6 inclusive the metal sheet 23 isprovided with parallel series of aligned but spaced slots 24 with thedistance between two adjacent set-s of aligned slots 24 determining thewidth of the n. Between each adjacent pair of series of aligned slots isarranged a series of openings 25 for receiving the tubes 26 of this rstembodiment. Each opening in this embodiment is surrounded by an annularange 27 that is struck from the sheet metal.

Between the openings 25 and the slot-s 24 are projections 28 struck fromthe sheet metal and arranged in pairs with one projection of each pairextending away from one side of the metal sheet and the other projectionextending away from the other side.

In order to produce the adjacent pleats constituting 'the spaced tinsthe metal sheet 23 is folded as illustrated in FIGURES 3 and 4 with theparallel series of aligned slots 24 determining the fold lines. As canbe seen in FIGURE 2, adjacent slots 24 are connected by relatively thinsections 29 of the sheet metal and these become the relatively narrowarcuate connections of one pleat or fin to its neighbor. Because thesesections 29 are thin, folding is easily accomplished at the sections sothat, in effect, each series of slots 24 determines a fold area for thesheet metal. As can be seen in FIGURE 5 the adjacent tins 30 which arethe same, of course, as the pleats are spaced from each other by theprojections 28. When the metal sheet is thusly folded the openings 25are in aligned series for receiving the fluid conduit tubes 26.

As can be seen from the above description the provision of spaced seriesof slots 24 aids in determining the fold areas for folding lthe metalsheet in sinuous fashion so that the adjacent pleats form the tins. Asthe adjacent tins are connected only by the relatively narrow metalsections 29, the folding is relatively easy. Furthermore, adjustmentsare easily made in the fold because the folding takes place at thesenarrow sections to align each set or series of tube openings 25 forreceiving the tubes 26. A very important function of these slots 24besides locating the fold areas is to permit fluid flow through theslots into the spaces between the tins and around the tubes 26. Thus, ithas always Ibeen possible to attain lluid flow, of course, between thetins at right angles to the plane of the View of FIGURE 1, for example,and parallel to the tins. Now, in addition to this direction of flow,fluid ilow is also achieved in additional directions through the slots(which would be at right angle-s to the plane of FIGURE 6) with thefolded arrangement providing substantially no interference to this flow.

The provision of the slots 24 has the further advantage of providingopenings for drainage of liquid such as condensate from an evaporatorsurface or cooling water from a condenser. This is particularlyimportant where the heat exchanger would be so constructed that thefoldareas are on the bottom. It is preferred for eflicient fluid ow betweenthe tins that the length of each slot 24 be at least of the fin width.

The embodiment shown in FIGURE 7 is quite similar to the embodiment ofFIGURES 2-6 inclusive. In FIG- URE 7, however, each s-lot or opening 31is of generally diamond shape with the long axis of each set of diamondsbeing aligned so that the sharper points 32 of the diamonds are adjacenteach other. In all other respects, this embodiment is the same as theprevious embodiment. In this construction the diamond formation locatessomewhat more precisely the fold line which will be essentially thealigned long axes of each set of diamond slots.

In the embodiment of FIGURES 8, 9 and 10 aligned slits 33 are usedinstead of the previous slots. Each set of slits is aligned with one endof one slit being spaced from the adjacent end of the other in order toprovide the connecting bridges or metal sections 34 which will connectthe adjacent pleats or ns 35. The metal sections 34 are defined on eachside by substantially parallel short slits 36 so that one slit 33 andits two end transverse short slits 36 form an H. In this embodiment thefins are formed by folding the metal sheet into pleats as in theprevious embodiments. Here, however, the fin edges 37 formed by the setsof slits 33 and 36 lie -in the planes of the respective ns 35 and arespaced from each other as shown in FIGURES 9 and 10.

The embodiment of FIGURES 8-10 has the advantages previously describedand in addition has the advantage of conserving useful fin metal forheat transfer purposes. Thus, in this embodiment the slits preserve allof the metal and do not eliminate metal as is true of the slots 24 and31 of the previous embodiments. Thus, a higher proportion of metal isavailable for heat transfer purposes. These resulting slit edges 37serve as liquid drip edges such as for dripping condensate when used asa part of a condenser for hot refrigerant.

The embodiment of FIGURES 11 and 12 is similar to the embodiment ofFIGURES 8, 9 and 10 in that slits 38 are used instead of the previouslydescribed slots. However, in the embodiment of FIGURES 11 and 12, eachlong slit 38 intersects an opening 39 for receiving tubes similar to thetubes 26. In this last embodiment the arrangement of the fins and tubesis similar to that of my prior application mentioned above. Thus, whenthe metal sheet 40 is folded to form the n structure 41, as shown inFIGURE 12, the aligned openings 39 at each edge of the fin structure areadapted to receive approximately one-half of a tube similar to the tube26. Then, another n structure can be placed on the opposite side of thetube in the manner shown in my above-mentioned prior application. Thisconstruction is possible here, as the connecting metal sections 42 thatare constructed similarly to the connecting sec tions 29 of the firstembodiment are located inwardly of the edges ofthe fins formed by theslits 38. Thus, the n structure 41 may be stacked with the slit edges ofone stack against the slit edges of a similar stack without interferenceby the recessed curved connecting sections 42.

In all embodiments the iin structure of the heat exchanger is made byfolding a metal sheet in alternate folds to provide adjacent pleatswhich constitute the plurality of tins. The folding is quite easilyaccomplished as the connecting portions of metal between the adjacentfins are relatively narrow sections. This has the added advantage ofproviding openings whether formed of slots where metal is actuallyremoved or slits where the metal is cut for receiving additional lluidsfor the spaces between the ns. The metal sheet may be as wide or asnarrow as desired to accommodate one coplanar set of tubes or aplurality of coplanar sets of tubes. Thus, in the portion of thestructure shown in FIGURE 2 the n structure will accommodate a set offour tubes. Dilferent arrangements and different ways of bending may ofcourse be used to produce any desired arrangement without departing from4the principles of the invention. In the embodiment shown substantiallyall of the fold areas on one side of the iin structure are in one planewhile those on the other side are in another parallel plane. Thedistances between these two planes have of course approximately thewidth of the fin.

Although the illustrated embodiments are for n structures eachaccommodating only one set of parallel tubes it is of course obviousthat the fold areas as determined by the slots or slits or otheropenings may be arranged to provide as many passes of parallel tubes asdesired. The single arrangement is illustrated for simplicity ofillustration of the invention.

Having described my invention as related to the embodiments shown in theaccompanying drawings, it is my intention that the invention be notlimited by any of the details of description, unless otherwise specied,

but rather be construed broadly within its spirit andy scope as set outin the accompanying claims.

I claim:

1. A fin and tube heat exchanger, comprising: a sinuous continuous metalsheet arranged in adjacent pleats constituting ns connected in series byside fold areas, said sheet having means forming elongated openingssubstantially along said fold areas for permitting high volume flow offluid through said openings and between said fins; means form-ingaligned 1in openings; and a plurality of tubes in said n openings inheat transfer relationship With said ns.

2. The structure of claim 1 wherein said fold area opening forming meanscomprise cut out sections in said sheet.

3. The structure of claim 1 wherein said fold area opening forming meanscomprise slits in said sheet.

4. The structure of claim 1 wherein said tube receiving openings are insaid alternate fold areas.

5. A 1in and tube heat exchanger, comprising: a sinuous continuous metalsheet arranged in adjacent pleats constituting ns having length andwidth connected in series by arcuately curved side fold areas and saidfins being substantially parallel to each other, alternate fold areasbeing located on opposite sides of said n structure with those on oneside being located substantially in a rst common plane and those on theopposite side being located substantially in a second common plane withthe two planes being substantially parallel to each other, said sheethaving means forming openings at said fold areas for permitting highvolume flow of fluid through said openings and between said ns with saidopenings having a length along said fold areas of at least about of saidn width and being arranged in alignment with one end of one openingspaced from the adjacent end of the next opening; means forming alignedfin openings; and a plurality of tubes in said fin openings in heattransfer relationship with said ns.

References Cited by the Examiner UNITED STATES PATENTS 2,119,761 6/1938Wentworth 165-152 X 2,788,195 4/1957 Karmazin 165--151 X 2,948,0548/1960 Kritzer 165-181 X 2,977,918 4/1961 Kritzer 165-181 X 2,994,1238/1961 Kritzer 165-151 X FOREIGN PATENTS 201,934 11/ 1924 Great Britain.

ROBERT A` OLEARY, Primary Examiner.

CHARLES SUKALO, Examiner.

1. A FIN AND TUBE HEAT EXCHANGER, COMPRISING: A SINUOUS CONTINUOUS METALSHEET ARRANGED IN ADJACENT PLEATES CONSTITUTING FINS CONNECTED IN SERIESBY SIDE FOLD AREA, SAID SHEET HAVING MEANS FORMING ELONGATED OPENINGSSUBSTANTIALLY ALONG SAID FOLD AREAS FOR PERMITTING HIGH VOLUME FLOW OFFLUID THROUGH SAID OPENINGS AND BETWEEN SAID